This invention describes the virtualization of computers, and more particularly to scheduling in a virtual processor.
Computer virtualization is a known technology. In computer virtualization, generally one or more physical processors are shared by time-sharing among multiple virtual computers. Specifically, multiple virtual computers comprise multiple virtual processors, and each of these multiple virtual processors can be scheduled to a physical processor.
In computer virtualization, it is desirable that each of the multiple virtual processors utilize the physical processors according to ratios proportionate to the service ratios of the multiple virtual computers. It is also desirable that the power consumption of the computer system be reduced while preventing a drop in the throughput of the computer system (for example, a server apparatus).
In Japanese Patent Laid-open Publication No. 2009-110404, there is disclosed technology related to the scheduling of an allocation of a virtual processor to a physical processor. According to Japanese Patent Laid-open Publication No. 2009-110404, when the operating frequency of a physical processor in a computer system drops, more processing time is allocated to a prescribed guest operating system (a guest OS).
In Japanese Patent Laid-open Publication No. 2009-140157, a method for increasing the number of physical processors in sleep mode by disassigning virtual processors in order to reduce the power consumption of the computer system is disclosed. The operating rate of the virtual processor is used as the criteria for assigning and disassigning a virtual processor to/from the physical processor. An allocation rate may also be set for each virtual processor. The operating frequency of the physical processor is determined based on the sum of the allocation rates of virtual processors assigned to the physical processor.